The seventh chords have in common that the seventh note in a scale is added to a triad (a three-note chord), making it a four-note chord (also called a tetrachord).
The name "dominant" refer to the fifth degree of the diatonic scale and it is called dominant because it is most weighty besides the tonic (the root of the scale) and its neither major nor minor. The most common dominant chord is a dominant seventh in which a minor seventh is added to a triad major. A less common alternative chord name for C7 is Cdom7 (dom stands for dominant). The seventh chord belongs also to the group of extended chords.
Note that the fifth sometimes are omitted when these chords are inverted. A slight dissonance could be heard in 7th chords because one of the notes, the seventh, is not included in the same key as the root note.
Major 7th is constructed by adding the seventh tone in the scale to a major triad.
Minor 7th is constructed by adding a minor seventh tone in the scale to a minor triad. Similar to the 7th chord, a slight dissonance could be heard in minor 7th chords because one of the notes, the seventh, is not included in the same key as the root note.
Make use of
How and when to use seventh chords? Seventh chords are common in many music styles, but especially in blues (major 7th not included) and jazz.
Chord sequences that shows how 7th chords can be utilized:
1. C7 F7 C7 G7 F7 C7
2. C7 F7 C7 Dm7 G7 F7 C7
3. C7 F7 C7 A7 Dm7 G7 C7
4. Dm7 G7 Cmaj7
(Typical blues and jazz progressions.)
Minor 7th flat 5 has a lowered fifth. This chord group is also known as half-diminished.
Additional seventh chords
Here are the other three groups of seventh chords, with examples in the note of C:
Cdim7: C – Eb – Gb – A
Caug7: C – E – G# – A#
CmM7: C – Eb – G – B
Alternate seventh chords
There are other seventh chords such as 7b5 and 7#9. For more variations of seventh chords, see Altered chords.
Major chords Minor chords Seventh chords Extended chords Sus chords Dim chords Aug Chords Add Chords Altered Chords